Effect of Dental Varnishes in Prevention of Enamel Demineralization Adjacent to Orthodontic Brackets

ABSTRACT

Aim:

The aim of the current research was to assess the ability of different dental varnishes in averting enamel demineralization adjoining the orthodontic brackets.

Materials and Methods:

Seventy-five premolars devoid of dental caries that were subjected to extraction for orthodontic purposes were employed in this research. The surface of enamel was etched with 37% phosphoric acid and subjected to primer application. Individual brackets were placed on the midregion of the buccal surfaces of the premolars with Transbond™ XT adhesive. Postbracket bonding, the dry premolar tooth samples were set aside cautiously. The samples were then allocated to three groups: Group I: Duraphat Varnish, Group II: Clinpro XT Varnish, and Group III: Profluorid Varnish. Every sample was independently subjected to immersion in demineralizing solution for a period of 96 h at 37°C in an incubator. Areas of demineralization were evaluated by documenting the microhardness along the severed surface using a microhardness tester equipped with a Vickers diamond.

Results:

The highest surface microhardness was noted with Profluorid Varnish group at 328.48 ± 1.12 in pursuit by Clinpro XT Varnish group at 322.08 ± 0.04 as well as Duraphat Varnish group at 307.42 ± 0.28 with a statistically noteworthy dissimilarity amid the groups.

Conclusion:

In conclusion, the three varnishes employed had an influence on the prevention of enamel demineralization surrounding the orthodontic brackets. Profluorid varnish however exhibited maximum efficiency in avoiding enamel demineralization versus Clinpro XT varnish as well as Duraphat varnish group.

INTRODUCTION

The process of losing calcified tooth substance is known as decalcification or demineralization. Regions of demineralized enamel appear clinically as “white-spot lesions” that manifest from modifications in the optic characteristics owing to mineral loss beneath the tooth surface. Acidic byproducts from bacterial micro-organisms in the dental plaque cause softening of the tooth structure. Such areas chiefly arise from an inequity amid phases of enamel demineralization/remineralization. White spots are hypothesized to be the initial signals of caries in the enamel.[1]

Areas representing demineralized enamel surrounding orthodontic brackets in course of orthodontic management occur commonly due to a lack of maintenance of good oral hygiene. Such demineralized regions lead to white-spot lesions on the surface of enamel in a majority of individuals undergoing orthodontic therapy, leading to unpleasant aesthetics and are additionally a threat to successful orthodontic management. Among the key reasons for such unwanted lesions are brackets/fixed orthodontic appliances, as they promote bacterial buildup by rendering regions facilitating retention.[2]

Plaque accretion additionally is enhanced by the employment of numerous arch wires, loops, as well as different elastics during orthodontic therapy. Highly frequent regions for plaque buildup are cervical areas immediately gingival to the bottom of the bracket, about surplus adhesive resources plus unfastened bands. Deprived oral hygiene as well as reduced patient obedience is critical in influencing the rate of enamel demineralization.[3] Orthodontic practitioners are well conscious of this matter and have made efforts to avoid it. Nevertheless, the demineralization of orthodontic fixed appliances persists to be problematic. A variety of techniques have been proposed to avert/reduce enamel demineralization but nearly all of these measures still rely on patient conformity, which is capricious.[4]

Topically applying fluorides in the form of fluoride comprising varnishes, gels, mouth rinses as well as toothpastes has been documented to be effective in avoiding dental caries as well as white-spot lesions in course of as well as following orthodontic therapy.[5] Therefore, the current research was performed to assess the ability of dissimilar dental varnishes in averting enamel demineralization adjoining the orthodontic brackets.

MATERIALS AND METHODS

Seventy-five premolars devoid of dental caries that were subjected to extraction for orthodontic purposes were employed in this research. The included teeth had an integral buccal surface with the absence of fractures/cracks and white spots. After taking off the remainder soft tissues using a scaler, the samples were subjected to storage in 0.1% thymol solution till further investigation. Prior to utilizing the samples for the study, the enamel surfaces were subjected to polishing with non-fluoride-containing pumice as well as water, rinsing under deionized water followed by drying with compressed air.

The surface of the enamel was etched with 37% of phosphoric acid for a period of 15 s, rinsed for 10 s, and finally subjected to drying. Application and polarization of Transbond™ XT primer were performed for 20 s. Individual brackets were placed on the midregion of the buccal surfaces of the premolars with Transbond™ XT adhesive. The surplus adhesive resin was eliminated.

Postbracket bonding, the dry premolar tooth samples were set aside cautiously. The samples were then allocated into three groups.

Group I: Duraphat Varnish: Enamel surface was subjected to a sole local application of a fluoride varnish using a brush applicator followed by permitting it to dry for 5 min.

Group II: Clinpro XT Varnish: The buccal surfaces of the samples were coated with Clinpro XT varnish surrounding the brackets followed by permitting them to dry for 5 min.

Group III: Profluorid Varnish: The labial surfaces of the samples were coated with Profluorid varnish surrounding the brackets followed by permitting them to dry for 5 min.

Every sample was independently subjected to immersion in 2 mL demineralizing solution for a period of 96 h at 37°C in an incubator, and the same was changed once every 4 h. The solution comprised 2.2 mmol/L each of PO₄⁻/Ca²⁺ plus 50 mmol/L acetic acid with a pH of 4.4. With the intention of replicating the wearing of varnishes on the tooth surface secondary to mechanical forces, the samples were subjected to a one-time manual brushing with a soft-bristled toothbrush. The teeth were not subjected to a reapplication of the varnish after the primary application. The samples were finally washed with water and placed in commercially obtainable artificial saliva (to produce an oral setting within the laboratory) for about 15 h until surface microhardness (SMH) assessment was performed.

Evaluation of surface microhardness (SMH)

Areas of demineralization were evaluated by documenting the microhardness along the severed surface using a microhardness tester equipped with a Vickers diamond. Assessments were performed beneath a 200 g load for 5 s. Fifteen indentations were created in every half of the crown. Three areas were chosen: periphery of the bracket bottom (0 μm) and at 100 and 200 μm from the occlusal aspect. For each area, five indentations were created on the external enamel surface.

Statistical analysis

Data were analyzed using Statistical Package for Social Sciences (SPSS) version 20.0. Calculation of the mean and standard deviation was done. The avoidance of enamel demineralization about orthodontic brackets was calculated with the one-way analysis of variance (ANOVA). Statistical significance was set at a P value < 0.05.

RESULTS

Table 1 depicts the mean surface microhardness of dissimilar dental varnish groups. The highest surface microhardness was noted with Profluorid Varnish group at 328.48 ± 1.12 in pursuit by Clinpro XT Varnish group at 322.08 ± 0.04 as well as Duraphat Varnish group at 307.42 ± 0.28 with a statistically noteworthy dissimilarity amid the groups.

Table 1.

Mean surface microhardness of different dental varnishes groups

Varnish Groups	n	Mean ± SD	F	P	Significance
Group I: Duraphat Varnish	25	307.42 ± 0.28	28.018	0.001	HS
Group II: Clinpro XT Varnish	25	322.08 ± 0.04
Group III: Profluorid Varnish	25	328.48 ± 1.12

P<0.05, HS: Highly Significant

On the whole, a comparative assessment of dissimilar dental varnish groups employing the Tukey’s post hoc test showed statistically noteworthy differences amid Profluorid Varnish as well as Duraphat Varnish group and Clinpro XT group as well as Duraphat Varnish group. However, the Clinpro XT Varnish and Profluorid Varnish group did not depict any noteworthy distinction [Table 2].

Table 2.

Overall comparison of different dental varnishes groups using Tukey’s post hoc test

Groups	Comparison with	Mean Difference	Significance
Group I	Group II	−14.66	0.001
	Group III	−21.06	0.001
Group II	Group I	14.66	0.001
	Group III	−6.40	0.852
Group III	Group I	21.06	0.001
	Group II	6.40	0.852

DISCUSSION

The chief reasons for demineralized areas on enamel in course of orthodontic treatment is the total mineral quantity in enamel, build-up of plaque containing bacterial micro-organisms as well as the dietary habits of the patient. A reduction in the outcomes of such etiologies can prevent/reduce the occurrence of demineralizing areas on enamel. Though aids of prevention such as toothpastes and mouthwashes are efficient, they have not been completely victorious as they rely on execution by patients.[6]

The investigations on the actions of fluoride-containing varnishes exhibit greater efficiency in avoiding acidic confrontations as a result of them comprising more fluoride quantities and the characteristic of bonding to the tooth surface for periods greater than the varied local fluoride application resources. A dental physician must apply the fluoride varnish on a routine basis to harness the efficiency of fluoride varnishes as their higher fluoride content avoids decalcification and also renders a steady fluoride pool in the oral cavity.[7]

In the current research, maximum surface microhardness was established by the Profluorid Varnish versus Clinpro XT Varnish as well as Duraphat Varnish group. Profluorid varnish was noted to exhibit higher effectiveness compared with the remainder of substances studied in avoiding mineral loss from enamel beside the brackets. These inferences are in accordance with Nalbantgil et al.,[8] Vivaldi-Rodriques et al., and[9] Ulkur et al.[10] This is because Profluorid varnish creates CaF₂ build-up as well as causes F accretion in microscopic canals plus pores on the enamel surface, thereby deterring its demineralization.

To imitate demineralization as well as remineralization phases in saliva in the mouth, a laboratory pH-changing model was created; this was analogous to the research performed by Featherstone et al.[11] that inferred an exponential quantitative association between fluoride quantity as well as prevention of hydroxyapatite demineralization/augmentation of remineralization. In the current research, in vitro enamel surface microhardness was assessed after the application of three dissimilar varnishes. The Vickers hardness measuring investigation was employed to evaluate microhardness, postreplication of oral settings in the laboratory. The pH cycling technique produces an oral situation in the laboratory by producing acid tests. However, the entire reproduction of oral settings may not be anticipated in the laboratory due to the significant and crucial parameters connected to the remineralization procedure like flow rate plus the pace of saliva, its contents, as well as buffering ability.[12]

The ultimate aim of this in vitro research was to assess the most superior key for enamel demineralization in course of orthodontic management in individuals. However, it is suggested that this goal be accomplished by an in vivo research that balances the results appropriately, as the interval of the varnish coating is diverse in reality. It is additionally suggested that before orthodontic therapy, the vulnerability of the patient is evaluated to help chose a highly superior varnish treatment.

CONCLUSION

In conclusion, the three varnishes employed had an influence on the prevention of enamel demineralization surrounding the orthodontic brackets. Profluorid varnish however exhibited maximum efficiency in avoiding enamel demineralization versus Clinpro XT varnish as well as Duraphat varnish group.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.